U.S. patent application number 13/450941 was filed with the patent office on 2012-10-25 for system and method for deploying a downhole casing patch.
This patent application is currently assigned to SMITH INTERNATIONAL, INC.. Invention is credited to Ronald G. Schmidt, James A. Simson.
Application Number | 20120267099 13/450941 |
Document ID | / |
Family ID | 47020402 |
Filed Date | 2012-10-25 |
United States Patent
Application |
20120267099 |
Kind Code |
A1 |
Simson; James A. ; et
al. |
October 25, 2012 |
SYSTEM AND METHOD FOR DEPLOYING A DOWNHOLE CASING PATCH
Abstract
A casing patch and methods for using same are provided. The
patch can include a hollow, substantially tubular body. An opening
can be formed in the body. A tapered slot can be formed in the body
below the opening. A width of the tapered slot proximate the
opening can be greater than the width of the tapered slot distal
the opening. The tapered slot can be adapted to receive a tapered
wedge and expand radially outward as the tapered wedge slides
within the tapered slot and away from the opening.
Inventors: |
Simson; James A.; (Meadows
Place, TX) ; Schmidt; Ronald G.; (Tomball,
TX) |
Assignee: |
SMITH INTERNATIONAL, INC.
Houston
TX
|
Family ID: |
47020402 |
Appl. No.: |
13/450941 |
Filed: |
April 19, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61477350 |
Apr 20, 2011 |
|
|
|
Current U.S.
Class: |
166/277 ;
138/98 |
Current CPC
Class: |
E21B 23/01 20130101;
E21B 29/10 20130101; E21B 43/103 20130101 |
Class at
Publication: |
166/277 ;
138/98 |
International
Class: |
E21B 29/10 20060101
E21B029/10; F16L 55/16 20060101 F16L055/16 |
Claims
1. A patch for repairing a casing in a wellbore, comprising: a
hollow, substantially tubular body; an opening formed in the body;
and a tapered slot formed in the body below the opening, wherein a
width of the tapered slot proximate the opening is greater than the
width of the tapered slot distal the opening, and wherein the
tapered slot is adapted to receive a tapered wedge and to expand
radially outward as the tapered wedge slides within the tapered
slot and away from the opening.
2. The patch of claim 1, wherein the tapered slot comprises
axially-extending sides that are oriented at an angle with respect
to a longitudinal center line through the body between about
1.degree. and about 45.degree..
3. The patch of claim 2, wherein the axially-extending sides of the
tapered slot are oriented helically along the longitudinal center
line through the body.
4. The patch of claim 1, wherein the tapered slot receives the
tapered wedge, and wherein the tapered wedge comprises
axially-extending sides that are oriented at an angle with respect
to a longitudinal center line through the body between about
1.degree. and about 45.degree..
5. The patch of claim 4, wherein the axially-extending sides of the
tapered wedge are oriented helically along the longitudinal center
line through the body.
6. The patch of claim 1, wherein the tapered slot and the tapered
wedge each comprise axially-extending sides, wherein the
axially-extending sides of the tapered slot engage the
axially-extending sides of the tapered wedge, and wherein profiles
of the axially-extending sides of the tapered slot and the
axially-extending sides of the tapered wedge are oriented helically
along a longitudinal center line through the body.
7. The patch of claim 1, wherein a ratio of a width of the opening
to a diameter of the body is between about 0.2:1 and about 1:1, and
a ratio of an axial length of the opening to the diameter of the
body is between about 1:1 and about 8:1.
8. The patch of claim 1, the opening is shaped and sized to adapt
to a shape and size of the tapered slot.
9. The patch of claim 1, wherein the body comprises one or more
holes formed therethrough and above the opening, wherein the one or
more holes are adapted to have an adhesive flow therethrough.
10. The patch of claim 9, wherein the body further comprises a
circumferential barrier disposed between the one or more holes and
the opening, wherein the circumferential barrier extends radially
outward from the body and is adapted to form a seal between the
body and an inner surface of a casing.
11. A system for repairing a casing in a wellbore, comprising: a
patch, comprising: a hollow, substantially tubular body; an opening
formed in the body; and a tapered slot formed in the body below the
opening, wherein a width of the tapered slot proximate the opening
is greater than the width of the tapered slot distal the opening;
an anchoring tool at least partially disposed within the patch,
wherein the anchoring tool is adapted to move a tapered wedge
within the tapered slot to expand at least a portion of the patch
radially outward and into contact with an inner surface of the
casing to anchor the patch in place with respect to the casing; and
an expansion tool coupled to the anchoring tool, wherein the
expansion tool is adapted to expand at least a portion of the patch
radially outward and into contact with the inner surface of the
casing when the expansion tool is pulled through the patch.
12. The system of claim 11, further comprising one or more shear
screws coupling the anchoring tool to the tapered wedge, wherein
the one or more shear screws are adapted to break when exposed to a
predetermined force.
13. The system of claim 11, further comprising an injection tool
coupled to the anchoring tool and at least partially disposed
within the patch, wherein the injection tool is adapted to
introduce an adhesive into an annulus formed between an outer
surface of the patch and the inner surface of the casing.
14. The system of claim 13, wherein the adhesive comprises an epoxy
resin and a hardener.
15. The system of claim 14, wherein the epoxy resin and the
hardener are mixed together downhole.
16. A method for repairing a casing in a wellbore, comprising:
running a patch into the wellbore, wherein the patch comprises: a
hollow, substantially tubular body; an opening formed in the body;
and a tapered slot formed in the body below the opening, wherein a
width of the tapered slot proximate the opening is greater than the
width of the tapered slot distal the opening; anchoring at least a
portion of the patch to an inner surface of the casing with an
anchoring tool disposed at least partially within the patch; and
expanding the patch radially outward with an expansion tool after
the portion of the patch has been anchored to the inner surface of
the casing.
17. The method of claim 16, wherein anchoring at least a portion of
the patch to the inner surface of the casing further comprises
moving a tapered wedge within the tapered slot with the anchoring
tool.
18. The method of claim 17, further comprising breaking one or more
shear screws that couple the tapered wedge to the anchoring tool
after the portion of the patch is anchored to the inner surface of
the casing.
19. The method of claim 16, further comprising injecting an
adhesive into an annulus formed between an outer surface of the
patch and the inner surface of the casing with an injection
tool.
20. The method of claim 19, further comprising mixing an epoxy
resin and a hardener together to form the adhesive when the
injection tool is downhole.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of and priority to U.S.
provisional patent application having Ser. No. 61/477,350 that was
filed on Apr. 20, 2011, which is incorporated by reference herein
in its entirety.
BACKGROUND
[0002] The present disclosure relates generally to a system and
method for deploying a downhole casing patch.
[0003] Oil and gas wells are ordinarily completed by cementing
metallic casing strings in the wellbore. During the drilling,
completion and production phase, operators may find it necessary to
perform remedial work, repair and maintenance to the casing. For
example, the casing is commonly perforated using an explosive
charge to evaluate various formations. In addition to the intended
perforations, unintentional holes or defects may also be created in
the casing. This can allow a leak to develop in the casing
permitting the loss of well fluids to a low pressure, porous zone
outside the casing, or permit an unwanted formation fluid, such as
water, to enter the well. Regardless of the specific application,
it is often necessary to deploy a patch to a downhole casing to
seal the wellbore from the external formation.
[0004] Numerous methods have been developed over the years to
deploy patches in casing. One method includes coating a
longitudinally corrugated liner with a thin layer of epoxy resin
(or other cementing material) and a glass fiber cloth prior to
deployment in the wellbore. The coated liner is run into the
wellbore (to the damaged area) on a tubing string and then expanded
against the casing by forcing an expander device (e.g., a cone)
through the liner. While this methodology has been commercially
utilized, application of the epoxy resin can be problematic. For
example, engagement of the coated liner with the wellbore wall
(especially in deviated wells) can cause a loss of the epoxy resin
and fiber materials during deployment. Such loss tends to result in
an inadequate seal between the patch and the casing. Moreover, the
cure cycle of the epoxy begins when mixing is complete. As such,
any delay during deployment of the patch can result in premature
curing of the epoxy.
[0005] Another method includes a metallic tubular that is
hydraulically or mechanically expanded into contact with the casing
to create a mechanical seal that relies on the contact stress
between the expanded tubular and the casing. The metallic tubular
is made of a highly compliant material to improve the contact
resistance and therefore better seal the damaged section. This
tends to require large pressures to expand the tubular and a
tubular patch fabricated from an expensive alloy to obtain an
effective seal.
[0006] Swage style patches are also known in the art and make use
of hydraulically or mechanically deformable swages to seal the
upper and lower ends of the patch. A conventional threaded tubular
patch is deployed between and coupled with the swages. The damaged
section is thereby straddled and isolated by the swages and
tubular. While swage style patches provide an effective seal, they
also tend to create a restriction in the wellbore, since the
tubular patch is not expanded.
[0007] Epoxy only patches are also known in the art and make use of
an epoxy resin that is pumped downhole to the damage section. After
curing, the wellbore is re-drilled to remove any excess epoxy.
While such patches are sometimes effective, they rely only on the
properties of the epoxy for their strength. As such, the epoxy-only
patch is typically ineffective at high pressures.
[0008] There remains a need in the art, therefore, for new casing
patches and methods for deploying patches in a subterranean cased
wellbore.
SUMMARY
[0009] This summary is provided to introduce a selection of
concepts that are further described below in the detailed
description. This summary is not intended to identify key or
essential features of the claimed subject matter, nor is it
intended to be used as an aid in limiting the scope of the claimed
subject matter.
[0010] Systems and methods for repairing a casing in a wellbore are
provided. The system can include a hollow, substantially tubular
body. An opening can be formed in the body. A tapered slot can be
formed in the body below the opening. A width of the tapered slot
proximate the opening can be greater than the width of the tapered
slot distal the opening. The tapered slot can be adapted to receive
a tapered wedge and to expand radially outward as the tapered wedge
slides within the tapered slot and away from the opening.
[0011] The method can include running a patch into a wellbore. The
patch can include a hollow, substantially tubular body. An opening
can be formed in the body, and a tapered slot can be formed in the
body below the opening. A width of the tapered slot proximate the
opening can be greater than the width of the tapered slot distal
the opening. At least a portion of the patch can be anchored to an
inner surface of the casing with an anchoring tool disposed at
least partially within the patch. The patch can be expanded
radially outward with an expansion tool after the portion of the
patch has been anchored to the inner surface of the casing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] So that the recited features can be understood in detail, a
more particular description, briefly summarized above, can be had
by reference to one or more embodiments, some of which are
illustrated in the appended drawings. It is to be noted, however,
that the appended drawings illustrate only exemplary embodiments
and are therefore not to be considered limiting of its scope, for
the invention can admit to other equally effective embodiments.
[0013] FIG. 1 depicts a cased wellbore having a tool string
disposed therein, according to one or more embodiments
disclosed.
[0014] FIG. 2 depicts an illustrative method for patching the
defect in the casing, according to one or more embodiments
disclosed.
[0015] FIGS. 3A-3C depict cross-sectional views of an illustrative
tool string and patch, according to one or more embodiments
disclosed.
[0016] FIG. 4 depicts a cross-sectional view of an illustrative
ball seat assembly or tool, according to one or more embodiments
disclosed.
[0017] FIG. 5A depicts a cross-sectional view of a portion of an
illustrative patch, and FIG. 5B depicts a perspective view of an
illustrative tapered locking wedge, according to one or more
embodiments disclosed.
[0018] FIGS. 6A and 6B depict a perspective view and a
cross-sectional view, respectively, of an illustrative anchor tool,
according to one or more embodiments disclosed.
[0019] FIGS. 7A and 7B depict cross-sectional views of an
illustrative injection tool, according to one or more embodiments
disclosed.
[0020] FIGS. 8A and 8B depict cross-sectional views of an
illustrative expansion tool, according to one or more embodiments
disclosed.
[0021] FIG. 9 depicts a cross-sectional view of another
illustrative expansion tool, according to one or more embodiments
disclosed.
[0022] FIGS. 10A and 10B depict cross-sectional views of an
illustrative bulger assembly, before and after actuation, according
to one or more embodiments disclosed.
DETAILED DESCRIPTION
[0023] FIG. 1 depicts a cased wellbore 40 having a tool string 200
disposed therein, according to one or more embodiments. The
wellbore 40 can be disposed proximate a subterranean oil or gas
formation. The wellbore 40 can be at least partially cased with one
or more casing strings or casings 50. The casing 50 can include a
defect 52 (e.g., a perforation, crack, and/or hole) that requires
patching. Accordingly, a tool string 200 can be lowered from a rig
20 and into the wellbore 40. The tool string 200 can include a
substantially tubular patch configured to repair or seal the defect
52 in the casing 50.
[0024] FIG. 2 depicts an illustrative method 100 for patching the
defect 52 in the casing 50, according to one or more embodiments.
The method 100 is described with reference to the tool string 200
depicted in FIGS. 1 and 3A-3C. A tubular patch 300 can be disposed
on, in, and/or around the tool string 200 and positioned in the
casing 50 proximate the defect 52, as shown at 102. The patch 300
can be anchored to an inner surface of the casing 50, for example,
using an anchoring tool 240, as shown at 104.
[0025] Once anchored, the patch 300 can be expanded into contact
with the inner surface of the casing 50. For example, an expansion
tool 350 can be traversed or pulled in the uphole direction through
the patch 300, as shown at 108. As used herein, the term "uphole"
refers to a direction that is toward the surface and/or the rig 20,
or a position that is closer to the surface and/or the rig 20 than
another position. The term "downhole" refers to a direction that is
away from the surface and/or the rig 20, or a position that is
within the cased wellbore 40, i.e., below the Earth's surface.
[0026] In one or more embodiments, a sealant or adhesive material,
such as an epoxy resin for example, can be used to provide a better
seal or adherence between the patch 300 and the casing 50. The
sealant or adhesive material can be applied to the patch 300 before
the patch 300 is lowered into the wellbore 50. Alternatively, the
sealant or adhesive material can be applied to the patch 300 after
it has been located in the wellbore 50. For example, the sealant or
adhesive material can be injected between an outer surface of the
patch 300 and the inner surface of the casing 50 using an injection
tool 270, as shown at 106. In the case of an epoxy resin, the epoxy
resin can be mixed with a hardener downhole to form the adhesive
mixture after the patch 300 is located in the casing 50. The epoxy
resin and the hardener can be mixed together simultaneously with or
subsequent to the patch 300 being anchored to the inner surface of
the casing 50.
[0027] FIGS. 3A-3C depict cross-sectional views of an illustrative
tool string 200 (FIG. 1) and patch 300, according to one or more
embodiments. The tool string 200 can include a ball seat assembly
220, anchoring assembly 240, expansion assembly 350, and optionally
an injection assembly 270. The expansion tool 350 can be disposed
above and threadably coupled to the ball seat assembly 220. Then
anchoring assembly 240 can be disposed above and threadably coupled
to the expansion tool 350. If needed, the injection tool 270 can be
disposed above and threadably coupled to the anchoring tool 240. As
used herein, the terms "couple," "coupled," "connect,"
"connection," "connected," "in connection with," and "connecting"
refer to "in direct connection with" or "in connection with via
another element or member." The terms "up" and "down"; "upper" and
"lower"; "upwardly" and "downwardly"; "upstream" and "downstream";
"above" and "below"; and other like terms as used herein refer to
relative positions to one another and are not intended to denote a
particular direction or spatial orientation.
[0028] FIG. 4 depicts a cross-sectional view of an illustrative
ball seat assembly or tool 220, according to one or more
embodiments. The ball seat assembly 220 can include a housing or
body 222 having threaded ends. A ball seat 224 can be disposed in
the housing 222 and secured in place with one or more shear screws
226. In at least one embodiment, the ball seat 224 can be shaped
and sized to accommodate a ball or other sealing mechanism 228. For
example, the ball seat 224 can be curved or frustoconical and have
an aperture 227 formed therethrough. The ball or sealing mechanism
228 can provide a seal against the aperture 227 to prevent fluid
flow in at least one direction through the assembly 220. The ball
or sealing mechanism 228 can be made of any suitable material. In
one or more embodiment, the ball or sealing mechanism 228 can be a
steel ball, a thermoplastic ball, a dart, or the like.
[0029] After the patch 300 has been positioned proximate the defect
52 in the casing 50 (e.g., step 102 in method 100), the ball 228
can be dropped from the surface and engage the ball seat 224 to
prevent fluid flow in at least one direction therethrough. In
deviated wellbores, gravitational force alone may not be sufficient
to move the ball 228 from the surface and into engagement with ball
seat 224. As such, in deviated wellbores, a liquid, such as a
drilling fluid, can be introduced or injected into the wellbore 40
to force the ball 228 deeper into the wellbore 40 (e.g., along the
horizontal section of the wellbore 40) and into contact with the
ball seat 224.
[0030] Once the ball 228 is located within the seat 224, hydraulic
pressure can build within the internal bore of the tool string 200.
Once the internal hydraulic pressure reaches a predetermined level,
the anchoring tool 240 and/or the injection tool 270 can actuate,
as described in more detail below. Upon completion of the anchoring
and injection steps (e.g., steps 104 and 106 in method 100), the
hydraulic pressure in the internal bore of the tool string 200 can
be increased until the shear screw 226 shears or breaks, allowing
the ball seat 224 to drop and reestablishing fluid flow through
ball seat assembly 220.
[0031] Considering the patch 300 in more detail, FIG. 5A depicts a
cross-sectional view of a portion of the patch 300, according to
one or more embodiments. The patch 300 can include a substantially
tubular, thin-walled (i.e., hollow) body 302 disposed around a
portion of the tool string 200. The patch 300 can be made from a
metal. In at least one embodiment, the patch 300 can be made from
steel or stainless steel. The patch 300 can have a length ranging
from a low of about 1 m, about 2 m, or about 3 m to a high of about
6 m, about 8 m, about 10 m, or more. The patch 300 can have a
cross-sectional length, e.g., diameter, ranging from a low of about
10 cm, about 15 cm, or about 20 cm to a high of about 30 cm, about
40 cm, about 50 cm, or more.
[0032] The patch 300 can have one or more expansion relief windows
or openings (one is shown 306) formed therein. The opening 306 can
reduce the stress on the patch body 302 when the patch 300 is
expanded radially outward, e.g, during anchoring step 104. The
opening 306 can be substantially rectangular having a width
measured along the circumference of the patch body 302 and a length
measured in the axial direction. A ratio of the width of the
opening 306 to the diameter of the patch body 302 can range from a
low of about 0.1:1, about 0.2:1, or about 0.4:1 to a high of about
0.6:1, about 0.8:1, about 1:1, or more. For example, the width of
the opening 306 can range from a low of about 5 cm, about 10 cm, or
about 15 cm to a high of about 20 cm, about 30 cm, about 40 cm, or
more. A ratio of the length of the opening 308 to the diameter of
the patch body 302 can range from a low of about 0.5:1, about 1:1,
about 2:1, or about 3:1 to a high of about 4:1, about 6:1, about
8:1, about 10:1, or more. For example, the length of the opening
306 can range from a low of about 20 cm, about 40 cm, about 60 cm,
about 80 cm, or about 1 m to a high of about 1.2 m, about 1.4 m,
about 1.6 m, about 1.8 m, about 2 m, or more.
[0033] A tapered (V-shaped) slot 308 can be formed in the patch 300
proximate a lower end of the opening 306. As shown, the tapered
slot 308 can be in communication with the opening 306. A width of
the tapered slot 308, as measured along the circumference of the
patch body 302, proximate the opening 306 can be greater than the
width of the tapered slot 308 distal the opening 306. For example,
the sides of the tapered slot 308 can be oriented at an angle with
respect to a longitudinal center line through the patch body 302
ranging from a low of about 1.degree., about 2.degree., about
4.degree., about 6.degree., about 8.degree., or about 10.degree. to
a high of about 15.degree., about 20.degree., about 25.degree.,
about 30.degree., about 35.degree., about 40.degree., about
45.degree., or more. The tapered slot 308 can be adapted to receive
a tapered wedge 320, as described in more detail below.
[0034] The patch body 302 can also include one or more protrusions
or upsets 305 formed below the opening 306 and/or proximate the
tapered slot 308. The upsets 305 can extend radially outward from
the patch body 302 to increase the contact stress or force between
the patch body 302 and the inner surface of the casing 50 (FIG. 1).
For example, each upset 305 can extend radially outward beyond the
outer surface of the patch body 302 by about 0.5 mm, about 1 mm,
about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 8
mm, about 10 mm, or more. Each upset 305 can have a height or axial
length ranging from about 1 mm, about 2 mm, about 5 mm, or about 1
cm to about 2 cm, about 4 cm, about 6 cm, about 8 cm, about 10 cm,
or more. When two or more upsets 305 are used, the axial spacing
between the upsets 305 can range from about 1 mm, about 2 mm, about
5 mm, or about 1 cm to about 2 cm, about 4 cm, about 6 cm, about 8
cm, about 10 cm, or more. By reducing the surface area in contact
with the inner surface of the casing 50, the upsets 305 can
increase the contact stress or force between the patch body 302 and
the inner surface of the casing 50. Accordingly, the upsets 305 can
improve the anchoring ability of the patch body 302 within the
casing 50.
[0035] A ring or web 312 can be formed proximate the lower end of
the tapered slot 308. The ring 312 can be a portion of the patch
body 302 that extends, at least partially, around the circumference
of the body 302. As such, the ring 312 can prevent the patch body
302 from prematurely expanding during deployment in the wellbore
40. The ring 312 can have a height or axial length ranging from a
low of about 0.5 cm, about 1 cm, or about 2 cm to a high of about 4
cm, about 6 cm, about 8 cm, or more.
[0036] The patch body 302 can also include a plurality of ports 314
formed above the expansion opening 306 through which adhesive may
be injected (e.g., during injection step 106--FIG. 2). Any number
of ports 314 can be used. The ports 314 can be circumferentially
and/or axially spaced apart around the patch body 302. In at least
one embodiment, a resilient barrier cup 304, e.g., formed of a thin
metallic material, can be at least partially disposed about the
patch body 302 and below the injection ports 314. The barrier cup
304 can form a seal with an inner surface of the casing 50 to
prevent injected adhesive from traveling in the downhole direction
through the annulus towards the opening 306. Rather than a barrier
cup 304, an extension (see 303 in FIG. 10B) can be formed in the
patch body 302 below the injection ports 314.
[0037] FIG. 5B depicts a perspective view of an illustrative
tapered locking wedge 320, according to one or more embodiments.
The tapered wedge 320 can be located or disposed within the tapered
slot 308 and adapted to help anchor the patch 300 against the
casing 50, as described in more detail below. The tapered wedge 320
can be made from a metal, such as a hardened steel alloy and have a
radius of curvature to match the patch body 302. As such, the
tapered wedge 320 can be adapted to slide axially within the
tapered slot 308. And as with the tapered slot 308, the width of
the tapered wedge 320 can decrease in the downhole direction. For
example, the sides of the tapered wedge 320 can be oriented at an
angle with respect to a longitudinal center line through the patch
body 302 ranging from a low of about 1.degree., about 2.degree.,
about 4.degree., about 6.degree., about 8.degree., or about
10.degree. to a high of about 15.degree., about 20.degree., about
25.degree., about 30.degree., about 35.degree., about 40.degree.,
about 45.degree., or more. In at least one embodiment, the sides of
the tapered wedge 320 can have a profile adapted to engage the
sides of the tapered slot 308.
[0038] The axially-extending sides of the tapered slot 308 and the
axially-extending sides of the tapered wedge 320 can each have a
helical profile. In other words, when the tapered wedge 320 is
engaged with the tapered slot 308, the upper or uphole end of the
tapered slot 308 can be disposed radially outward from the lower or
downhole end of the tapered slot 308 with respect to a longitudinal
center line through the body 302. Similarly, the upper or uphole
end of the tapered wedge 320 can be disposed radially outward from
the lower or downhole end of the tapered wedge 320 with respect to
the longitudinal center line through the body 302. Accordingly, the
helical profile of the tapered slot 308 and the tapered wedge 320
can cause the force between axially extending sides of the tapered
slot 308 and the tapered wedge 320 to be circumferential.
[0039] The axially-extending sides of the tapered wedge 320 can
also include a groove 322 adapted to receive a protrusion formed in
the sides of the tapered slot 308, or vice versa. However, as may
be appreciated, the axially-extending sides of the tapered slot 308
and tapered wedge 320 can be formed in any manner to form a track
to prevent the tapered wedge 320 from becoming disengaged with the
tapered slot 308 as the tapered wedge 320 slides therein.
[0040] The tapered wedge 320 can further include a plurality of
holes 324 through which the wedge 320 can be coupled to the
anchoring tool 240. For example, one or more shear screws 253
(shown in FIG. 6B) can be disposed through the holes 324 to couple
the tapered wedge 320 to the anchoring tool 240, as described in
more detail below.
[0041] The tapered wedge 320 can also include a plurality of
wickers or teeth 325 formed in the outer surface thereof. The
wickers 325 can be adapted to engage (bite) the inner surface of
the casing 50 to prevent axial motion of tapered wedge 320 in the
uphole direction (e.g., during expansion step 108 in FIG. 2). The
wickers 325 can extend radially outward from the tapered wedge 320
by about 0.1 mm, about 0.2 mm, about 0.5 mm, or about 1 mm to about
2 mm, about 3 mm, about 4 mm, about 5 mm, or more.
[0042] When the patch 300 is disposed adjacent the defect 52 in the
casing 50, the anchoring tool 240 can move the tapered wedge 320
downward in the tapered slot 308. As the tapered wedge 320 moves
downward, the portion of the patch 300, i.e., patch body 302,
proximate the tapered slot 308 can expand radially outward and
contact the casing 50. For example, the upsets 305 can contact the
casing 50. The contact between the patch 300 and the casing 50 can
anchor the patch 300 in place, thereby substantially preventing
axial movement of the patch 300 with respect to the casing 50. Any
slippage of the patch 300 in the uphole direction can drive the
tapered wedge 320 deeper into the tapered slot 308, thereby
increasing the tangential force that secures the patch 300 in the
casing 50. Once a predetermined downward force has been applied to
the tapered wedge 320 (anchoring the patch 300 in the casing 50),
the shear screws 253 can shear or break, releasing or decoupling
the patch 300 and the tapered wedge 320 from the anchoring tool
240. The tool string 200 (including the expansion tool 350) can
then be pulled upward toward the surface. As the expansion tool 350
moves upward through the patch 300, it can expand the patch 300
radially outward and into contact with the casing 50, as described
in more detail below.
[0043] FIG. 6A depicts a perspective view of an illustrative
anchoring tool 240, and FIG. 6B depicts a cross-sectional view of
the anchoring tool 240, according to one or more embodiments. The
anchoring tool 240 can be sized and shaped to be disposed in the
interior of patch 300, as depicted in FIG. 3. A first "main" piston
250 and a second "locking" piston 260 can be disposed around a
piston rod 246. An upper end portion of the piston rod 246 can be
threadably engaged with an upper mandrel 242, which can be coupled
to the injection tool 270. A lower end portion 248 of the piston
rod 246 can be coupled to the expansion tool 350. The main piston
250 can also be coupled to a wedge carrier 252. The wedge carrier
252 can be coupled to the tapered wedge 320 (see FIG. 5B) via one
or more shear screws 253.
[0044] Hydraulic pressure can be communicated to surfaces 254, 262
of the corresponding main and locking pistons 250, 260 through one
or more radial bores 247 formed in the piston rod 246. Prior to
hydraulic activation, an outer surface of a dog 264 can be
substantially flush with an outer surface of a cylindrical sleeve
244. As the pressure increases, the locking piston 260 can be urged
upward, thereby moving the dog 264 up a ramp 265. Movement of the
dog 264 up the ramp 265 can cause the dog 264 to engage the patch
body 302 in the opening 306. Such engagement can prevent subsequent
axial movement of the patch body 302 in the downhole direction when
the tapered wedge 320 is driven into the tapered slot 308.
Increasing hydraulic pressure can also urge the main piston 250
against a sheer screw 255. At a predetermined hydraulic pressure,
the screw 255 can break or shear, thereby allowing downhole
movement of the main piston 250 and the wedge carrier 252 relative
to the piston rod 246. Such movement of the main piston 250 can
urge the tapered wedge 320 into the tapered slot 308. The wedge
carrier 252 can move in a radial direction as the main piston 250
urges the tapered wedge 320 into the tapered slot 308. Radial
movement of the tapered wedge 320 can allow it to follow the
expansion of patch body 302 caused by the wedging action.
[0045] The anchoring tool 240 can further include a fixed cone 268
coupled to the piston rod 246. The cone 268 can be sized and shaped
to provide a preliminary expansion (e.g., about 50% of the total
expansion) of the patch body 302 as the tool string 200 is drawn
uphole during expansion step 108. Such a preliminary expansion can
reduce the force requirements of expansion tool 350 during the
subsequent expansion.
[0046] In at least one embodiment, the anchoring tool 240 can be
spring actuated. U.S. Pat. No. 7,428,928 discloses a spring
actuated anchoring tool. This application is incorporated herein by
reference in its entirety to the extent consistent with the present
disclosure.
[0047] FIGS. 7A and 7B depict cross-sectional views of an
illustrative injection tool 270, according to one or more
embodiments. As shown, the injection tool 270 can include plurality
of moving pistons or tubes. For example, the injection tool 270 can
include a main piston 272, inner push tube 274, and outer push tube
276. Increasing hydraulic pressure can urge the main piston 272 in
the downhole direction and into contact with the inner push tube
274 and the outer push tube 276. The inner push tube 274 can engage
an epoxy resin piston 278, and the outer push tube 276 can engage a
hardener piston 280, or vice versa. As such, the push tubes 274,
276 can increase the pressure of the epoxy resin and hardener
disposed in corresponding chambers 282, 284.
[0048] At a substantially predetermined hydraulic pressure, one or
more burst discs 285 can rupture allowing the epoxy resin and
hardener to flow into a static mixing chamber 290. The static
mixing chamber 290 can include a number of tortuous elements 292
that alter the direction of fluid flow which causes the epoxy resin
and hardener to intermingle and form an adhesive mixture. The
adhesive mixture can exit the mixing chamber 290 through ports 295
(and ports 314 of patch body 302 of FIG. 5A) into the annular
region between the patch body 302 and the casing 50. A barrier cup
298 can, at least partially, prevent migration of the mixture
between the injection tool 270 and the patch body 302. As described
above, a barrier cup 304 (or extension 303) can also be disposed
around the patch body 302 (as depicted in FIG. 5A) to substantially
prevent the adhesive mixture from migrating in the downhole
direction toward the opening 306. The injection tool 270 can use
substantially any suitable formulation of epoxy resin/hardener. For
example, the epoxy resin and hardener can be mixed in a two-to-one
volume ratio.
[0049] FIGS. 8A and 8B depict cross-sectional views of an
illustrative expansion tool 350, according to one or more
embodiments. The expansion tool 350 can include a mandrel 352
disposed within a collet cone 354, a collet 356, and a spring
subassembly 360. The spring subassembly 360 can include a
Belleville spring stack 362 disposed between upper and lower
washers 364 and 365. The spring stack 362 can be biased (i.e.,
compressed) to provide a predetermined axial force urging the
collet 356 in the uphole direction. The collet 356 can include a
plurality of circumferentially spaced fingers that ride up on the
collet cone 354 into contact with a shoulder 355 of the cone
354.
[0050] During the expansion step 108 (FIG. 2), both the shoulder
355 of the collet cone 354 and the collet 356 can provide
additional expansion of the patch body 302. The collet cone 354 and
collet 356 can be sized and shaped so as to mechanically expand the
patch 300 radially outward and into contact (or near contact) with
the inner surface of the casing 50 as the tool string 200 is drawn
uphole. Maximum expansion can be provided when the collet 356 is
urged in the uphole direction into contact with the shoulder 355.
The spring stack 362 can provide a compliant mechanism that allows
the collet 356 to move axially downhole (at a predetermined force)
and the fingers to move radially inward should the expansion tool
350 encounter irregularities in the installed casing 50 (e.g.,
debris or a casing collar). Such axial and radial motion is
intended to minimize the likelihood of the tool 350 becoming stuck
in the casing 50 during the expansion step.
[0051] FIG. 9 depicts a cross-sectional view of another
illustrative expansion tool 370, according to one or more
embodiments. The expansion tool 370 can include a plurality of
circumferentially spaced flex segments 372 disposed between an
upper retainer 374 and a lower retainer 375 and around a flex
segment cone 376. The spring stack 362 can be biased to provide an
axial force that urges the flex segments 372 in the uphole
direction such that they ride up on the cone 376 and expand the
patch body 302 as the tool string 200 is drawn uphole. The spring
stack 362 can also provide a compliant mechanism that allows the
flex segments 372 to move axially downhole and radially inward
should the expansion tool 370 encounter irregularities in the
installed casing 50. The flex segments 372 and flex segment cone
376 can be sized and shaped so as to mechanically expand the patch
300 into contact (or near contact) with the inner surface of the
casing 50.
[0052] FIGS. 10A and 10B depict cross-sectional views of an
illustrative bulger assembly 400 before and after actuation,
according to one or more embodiments. The bulger assembly 400 can
replace the upper mandrel 242 in the anchoring tool 240 (see FIG.
6B) and form or create a seal between the patch body 302 and the
inner surface of the casing 50. The bulger assembly 400 can include
uphole and downhole body portions 405, 410. An axial piston 420 can
be disposed between the body portions 405, 410 and engage a bulger
element 425. The bulger element 425 can be fabricated from a
resilient material, such as a nitrile rubber, suitable for use in
the downhole environment. First and second extrusion rings 427, 428
can be disposed about the bulger element 425. The extrusion rings
427, 428 can have an L-shaped cross-section and be fabricated from
a low yield, highly ductile material such as brass. The bulger
assembly 400 can be disposed at substantially any suitable location
axially between injection port 314 and opening 306 of the patch
300.
[0053] During operation, hydraulic pressure can be communicated to
the surface 408 of axial piston 420 through one or more radial
bores 407 formed in body portion 405. As the pressure increases,
the axial piston 420 can be urged uphole, thereby compressing the
element 425 between the extrusion rings 427, 428. The element 325
can buckle radially outward into contact with the patch body 302,
thereby deforming the patch body 302 radially outward into the
inner surface of the casing, forming an extension 303, as best
illustrated in FIG. 10B. The extrusion rings 427, 428 can also
deform outward into contact with the patch body 302 and
substantially prevent axial extrusion of the element 325 into the
annular region on the inside of the patch body 302. The diameter of
the patch body 302 in the extension region can be increased by
about 1 cm, about 2 cm, about 3 cm, about 4 cm, about 5 cm, or
more. Further, the extension 303 can have a height or axial length
ranging from a low of about 1 cm, about 2 cm, about 3 cm, about 4
cm, about 5 cm, or more. The extension 303 can sealingly engage the
inner surface of the casing 50 to substantially prevent injected
epoxy from migrating in the downhole direction through the annulus
towards expansion opening 306.
[0054] Certain embodiments and features have been described using a
set of numerical upper limits and a set of numerical lower limits.
It should be appreciated that ranges from any lower limit to any
upper limit are contemplated unless otherwise indicated. Certain
lower limits, upper limits, and ranges appear in one or more claims
below. All numerical values are "about" or "approximately" the
indicated value, and take into account experimental error and
variations that would be expected by a person having ordinary skill
in the art.
[0055] Various terms have been defined above. To the extent a term
used in a claim is not defined above, it should be given the
broadest definition those in the pertinent art have given that term
as reflected in at least one printed publication or issued patent.
Furthermore, all patents, test procedures, and other documents
cited in this application are fully incorporated by reference to
the extent such disclosure is not inconsistent with this
application and for all jurisdictions in which such incorporation
is permitted.
[0056] While the foregoing is directed to embodiments of the
present disclosure, other and further embodiments of the invention
can be devised without departing from the basic scope thereof.
Accordingly, such other and further embodiments are intended to be
included in the scope of this disclosure.
* * * * *